The explosive growth of the “Internet of Things” is changing our world and the rapid drop in price for typical IoT components is allowing people to innovate new designs and products at home. In this first class in the specialization you will learn the importance of IoT in society, the current components of typical IoT devices and trends for the future. IoT design considerations, constraints and interfacing between the physical world and your device will also be covered. You will also learn how to make design trade-offs between hardware and software. We'll also cover key components of networking to ensure that students understand how to connect their device to the Internet. Please note that this course does not include discussion forums. Upon completing this course, you will be able to: 1. Define the term “Internet of Things” 2. State the technological trends which have led to IoT 3. Describe the impact of IoT on society 4. Define what an embedded system is in terms of its interface 5. Enumerate and describe the components of an embedded system 6. Describe the interactions of embedded systems with the physical world 7. Name the core hardware components most commonly used in IoT devices 8. Describe the interaction between software and hardware in an IoT device 9. Describe the role of an operating system to support software in an IoT device 10. Explain the use of networking and basic networking hardware 11. Describe the structure of the Internet 12. Describe the meaning of a “network protocol” 13. Explain MANETs and their relation to IoT
Lecture 3.2: Basic Equipment
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来自 University of California, Irvine 的课程
Introduction to the Internet of Things and Embedded Systems
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从本节课中
Embedded Systems
In Module 1, we introduced the concept of the Internet of Things at a high level, defining the term and outlining its implications. In this module we explore some of the details involved in the design and implementation of IoT devices. Unlike traditional computer-based systems, IoT devices are “embedded” within other devices in order to provide enhanced functionality without exposing the user to the complexities of a computer. The users interact with the device in a natural way, similar to their interactions with any other objects in the world. In this way, an embedded system has an interface that conforms to the expectations and needs of the users. Establishing a natural interface requires that the embedded system interface with the physical world directly through sensors, which read the state of the world, and actuators, which change the state of the world. In this module we will discuss the structure of embedded systems and describe these interactions with the physical world.
与讲师见面
Ian HarrisProfessor
Department of Computer Science
[MUSIC]
So in this lecture, we'll discuss some of the basic equipment
that you're going to be using when you're building your internet of things devices.
And some of the basic equipment that we'll be talking about through the class we'll
assume that you're using just to make things a little more concrete so you see.
I've been more generic in the earlier lectures
about the general type of equipment, but now we'll actually
point to the specific things that we're going to cover in this class.
Then when you do the capstone you'll be using this type of equipment when you do
your capstone.
So first, the main thing we're gonna use is a development board of some kind.
It's a board that has a microcontroller on it,
which is, of course, the center of all these projects.
The center of these systems is gonna be some microcontroller with some
code running on it.
So, the picture that we have here, is actually an arduino board.
And that black chip on the board, is actually the microcontroller itself.
Now, there's other hardware on the board.
There are interfaces like, for instance, you can see USB interface on the side.
There are a bunch of holes on the side that you can't see yet,
but those are plugs we're going to plug wires into.
We'll do that later.
There's a power.
And often there are other interfaces on the board.
So there are other interfaces on the board.
There are also the chips on the board and other devices on the board.
So there's the microcontroller, but
there are other things that are used on the board.
Generally the board, those development boards, what they are,
for the most part, the main thing they have to have is a microcontroller, that
you're gonna program, but also hardware on the board to program the microcontroller.
So basically, data has to get taken from the USB cable typically, so this has a USB
port, has to get taken from the USB cable, which is connected to your host.
Has to get taken from the USB and programmed into the flash memory of
the microcontroller, when you want to put a program onto the microcontroller.
So, typically these boards are minimally they will have equipment on there,
hardware on the board who's job it is to read the USB cable and
take the data that is received on there and program it onto the microcontroller.
That's sort of a minimum thing that you're going to find on these development boards.
A lot of different development boards have lots of different extra
equipment in addition to that.
Maybe you have compasses, accelerometer, magnetometer.
All sorts of extra components you can find on these boards.
Touch sensitive screens, all this stuff.
But the basic board is just what I've been talking about right now and
the boards that we're using, certainly Arduino is pretty basic.
It has basically what I just said.
That's an Arduino right there.
It has very little else besides the microcontroller,
the hardware used to program the microcontroller, plus the interfaces,
USB and the pins and stuff like that.
That's basically all an Arduino has on it.
Now, we're also going to use a Raspberry Pie and
we'll go into that in more detail later.
That has more things on it.
That actually has an accelerometer on it.
It has a magnetometer, meaning a compass.
It has a few other things on it.
But it's mostly pretty bare.
It has a processor on it too, a microcontroller on it, too.
I'll say it's a higher end microcontroller than what you find on our Arduino.
But that's the core of the system, so that's how we're gonna start.
We're gonna take these development boards, plug them in by USB to our host,
our laptop, desktop.
Write code on the laptop, desktop.
Program it onto the microcontroller on the development board.
Now other equipment you're gonna get.
USB cable, clearly, just to connect the board up.
Ethernet cable is a common piece of equipment I dont know if we'll be
using that.
But ethernet is common because a lot of these boards have ethernet cables,
have ethernet jacks because we want them to be networked, right?
We're talking about internet of things so it's common to have an ethernet jack.
Raspberry Pie does, standard Arduino does not.
But it's common that they have ethernet jacks and
then you would need an ethernet cable to connect to that.
Jumper wires.
So you're going to need a set of wires.
You'll get a set of wires to plug into the input pins of the board.
So that Arduino we saw on the last slide, it had several holes.
You can plug wires into those holes to connect up other things.
Different inputs.
These are components that we will commonly use as input components, so
essentially sensors.
So potentiometer,
potentiometer is a sensor that senses how much turn, sense of rotation.
So if you turn something more, turn to the left, turn to the right,
it changes the resistance between two signals.
And you can use that as a rotation sensor.
So if you wanna implement a volume knob or something like that,
you can use a potentiometer and sense how much it's turned.
Photoresistor, so that's something that senses the brightness.
So the brightness of the light will change the resistance on a certain resistor,
and you can sense that.
A keypad, that's another common component, just a bunch of buttons put together.
Buttons, individual buttons, that's another input and
common piece of equipment, and we'll have some of these.
Some of the outputs, LEDs, so those are light emitting diodes,
you've seen those little lights that turn off and on, light emitting diodes.
Resistors, we'll talk about those later, they don't do much.
They consume power and they change voltage for us, but simple components.
We're also going to use a breadboard.
Now a breadboard, actually I have a picture of that on the next slide.
So breadboards are for wiring.
So we're going to have a bunch of these components and
we're going to need to connect these components together.
So how do we connect them?
Well there are several ways.
One way is to solder things and we are not going to do that.
Soldering is a more permanent connection where you take two pieces of wire,
two pieces of metal you wanna connect, you'd take a hot iron touch it
to the joint, bring some solder which is softer metal,
you melt it onto the joint and it forms a seal and it connects them electrically.
So that soldering.
We won't do soldering, because soldering, well several things, but
the main thing is soldering is more permanent and we're just prototyping.
I mean, you're gonna be trying things and trying things again, trying things again.
Making mistakes, trying again.
So soldering is too time consuming.
Soldering is more permanent.
In the end, when you're done, you know everything works,
then you might solder things together.
But we're not in that mode, we're gonna be using a breadboard.
So breadboard is for non-permanent wiring.
So basically it's got a bunch of holes, a board with a bunch of holes.
And these holes fit 24 gauge wire, which is the common wire size for
components like this.
And these holes are connected electrically.
There are rows of five holes, you can see there, and if you put a wire into one
hole in a row of five, all the other holes in the same row of five are connected.
So you can plug two wires into two different holes on the same row of five
and they are connected.
And that's how you connect components.
So you can plug one connection from a component into one hole in the row and
plug another component into another hole in the same row, and
then those two components are connected.
Okay. So this is how we're going to be
doing wiring.
We're gonna have our breadboard and we connect things in that way.
And if you look at the breadboard, it's got these rows of five, but
then along the left and right sides, you got these columns, right.
These two columns on the left, two columns on the right with breaks in between.
But basically, two on the left, two on the right.
So those columns are actually wired differently.
They're not wired horizontally like those rows of five.
They're wired in columns.
So those two columns on the left, all holes in the same column are connected to
each other, and all holes in the next column are connected to each other.
Same thing on the other side.
All holes on the one column and all holes on the next are connected.
So traditionally those columns are used for power and
ground because usually when you make a system, you have a lot of chips and
a lot of different components in there and a lot of them need to receive power and
need to be connected to ground, so it helps to distribute power and
ground across the whole circuit to just put power and ground into those rows,
those columns, rather.
So, put power into one column.
Ground into another.
Then anything you want to connect to power and ground,
you don't have to run a long wire.
You just run a wire straight to that column, to the nearest hole on the column.
So, we'll be using breadboards to connect up our components and
it's very common for prototyping and it's made a specific size.
It's a common size.
Here's a typical circuit.
This is just one possible circuit but there's an Arduino.
And this Arduino, it's connected to some LEDs.
You can see those red LEDs that are in the breadboard, right.
So the LEDs are plugged into holes in the breadboard, the two leads.
An LED has two leads, two wires, that are connected to holes in the breadboard.
They're also resisters.
I don't know if you can see them.
But those little components that connect from the LEDs to the bottom row
that those are called resistors.
And we'll talk about that circuitry.
Basically you always want to put an LED in series with a resistor.
If not, then if you don't then what'll happen is you'll draw too much current
through the LED and you'll blow it out, it'll will burn out.
It will be very bright for a second and then you'll here a pop and
it will be gone.
You put resisters in there just to slow down the current,
basically to reduce the current.
Not slow it down but to reduce the amount of current that goes through.
And the other side of the LED is connected by those blue wires into the Arduino.
And the Arduino has some program running on it that probably turns on the LEDs,
turns them off and on in a particular sequence, or whatever you want it to do.
So those are the type of components that you will be using in the class, and
we'll be talking about in the class.
Thank you.
[MUSIC]
